Method for etching organic region

ABSTRACT

There is provided a method for etching an organic region of a substrate. In the method, an organic film is formed on a surface in a chamber of a plasma processing apparatus. The surface extends out around a region where the substrate is to be disposed in the chamber of the plasma processing apparatus, and the organic region is etched by chemical species from plasma in the chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2018-082127, filed on Apr. 23, 2018, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method for etching an organicregion.

BACKGROUND

In manufacturing electronic devices, plasma etching is performed on asubstrate. The plasma etching is performed in a state where thesubstrate is provided in a chamber of a plasma processing apparatus.Plasma of a processing gas is generated in the chamber. The substrate isetched with chemical species supplied from the plasma.

In plasma etching, it is required to etch the substrate while ensuringin-plane uniformity. In other words, high in-plane uniformity isrequired in plasma etching. Japanese Patent Application Publication No.2006-269879 discloses a technique for controlling an amount of gassupplied to a central region of a substrate and an amount of gassupplied to a peripheral region of the substrate to thereby obtain highin-plane uniformity in plasma etching.

Plasma etching may be performed to etch an organic region of thesubstrate. The high in-plane uniformity is also required in the plasmaetching of the organic region.

SUMMARY

In accordance with an aspect, there is provided a method for etching anorganic region of a substrate, including: forming an organic film on asurface in a chamber of a plasma processing apparatus, the surfaceextending out around a region where the substrate is to be disposed inthe chamber of the plasma processing apparatus; and etching the organicregion with chemical species from plasma in the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the present disclosure will become apparentfrom the following description of embodiments, given in conjunction withthe accompanying drawings, in which:

FIG. 1 is a flowchart of a method for etching an organic region of asubstrate according to an embodiment;

FIG. 2 is a partially enlarged cross-sectional view of an exemplarysubstrate to which the method shown in FIG. 1 can be applied;

FIG. 3 shows an exemplary plasma processing apparatus that can performthe method shown in FIG. 1;

FIG. 4 schematically shows an inner state of a chamber of the exemplaryplasma processing apparatus during execution of the method shown in FIG.1;

FIG. 5 is a partially enlarged cross-sectional view of the exemplarysubstrate after execution of step ST2 of the method shown in FIG. 1; and

FIGS. 6 to 8 schematically show inner states of the chamber of theexemplary plasma processing apparatus during the execution of the methodshown in FIG. 1.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings. Like reference numerals will be given to likeor corresponding parts throughout the drawings.

FIG. 1 is a flowchart of a method for etching an organic region of asubstrate according to an embodiment. A method MT shown in FIG. 1 isperformed to etch the organic region of the substrate. FIG. 2 is apartially enlarged cross-sectional view of an exemplary substrate towhich the method shown in FIG. 1 can be applied. The substrate W shownin FIG. 2 may have a substantially disc shape. The substrate W has anorganic region OR and a patterned region PR.

The organic region OR is made of an organic material. The patternedregion PR is provided on the organic region OR. The patterned region PRis used as a mask for plasma etching of the organic region OR. Thepatterned region PR is provided with one or more openings through whichthe organic region OR is partially exposed. The patterned region PR is,e.g., an anti-reflection film containing silicon. The patterned regionPR is formed by performing plasma etching on the anti-reflection filmhaving a resist mask formed thereon.

The substrate W may further have an underlying region UR. The organicregion OR is provided on the underlying region UR. The substrate W mayfurther have a film SF. The film SF is provided between the organicregion OR and the underlying region UR. The film SF may be a multilayerfilm or a monolayer film containing silicon. The film SF is, e.g., alaminated film including a silicon oxide film and a silicon film. Thefilm SF may be etched by plasma etching through a mask formed from theorganic region OR by executing step ST2 to be described later.

Hereinafter, the case in which the method MT is used for etching theorganic region OR of the substrate W shown in FIG. 2 will be describedas an example. The method MT can be applied to any substrate having anorganic region. The method MT is performed by using a plasma processingapparatus. FIG. 3 shows an exemplary plasma processing apparatus thatcan be used to perform the method shown in FIG. 1. The plasma processingapparatus 10 shown in FIG. 3 is a capacitively coupled plasma processingapparatus.

The plasma processing apparatus 10 includes a chamber 11. The chamber 11has an inner space S therein. The inner space S includes a first spaceS1 and a second space S2. The chamber 11 includes a chamber body 12. Thechamber body 12 has a substantially cylindrical shape. The chamber body12 has the inner space S therein. The chamber body 12 is made of, e.g.,aluminum. The chamber body 12 is frame grounded. A corrosion resistantfilm is formed on an inner wall surface of the chamber body 12, i.e., ona surface of the chamber body 12 that defines the inner space S. Thecorrosion resistant film may be a film formed by anodic oxidationtreatment, or a ceramic film made of yttrium oxide.

A heater HT2 (e.g., resistance heating element) is provided in thechamber body 12, e.g., in a sidewall of the chamber body 12. The heaterHT12 generates heat by power supplied from a heater controller HC12.

A passage 12 p is formed in the sidewall of the chamber body 12. Thesubstrate W is transferred between the inner space S and the outside ofthe chamber 11 through the passage 12 p. The passage 12 p can be openedand closed by a gate valve 12 g. The gate valve 12 g is provided alongthe sidewall of the chamber body 12.

A partition wall 14 is provided in the inner space S. The partition wall14 extends on the boundary between the first space S1 and the secondspace S2. A plurality of through-holes is formed in the partition wall14 so that the first space S1 and the second space S2 communicate witheach other therethrough. The partition wall 14 may be formed by forminga corrosion resistant film on a surface of a base. The corrosionresistant film may be a film formed by anodic oxidation treatment, or aceramic film made of yttrium oxide. The base is made of, e.g., aluminum.An opening is formed in the partition wall 14 to face the passage 12 p.The substrate W is transferred between the first space S1 and theoutside of the chamber 11 through the passage 12 p and the opening ofthe partition wall 14. The opening of the partition wall 14 can beopened and closed by a shutter SH. A heater HT14 (e.g., resistanceheating element) is provided in the partition wall 14. The heater HT14generates heat by power supplied from a heater controller HC14.

The partition wall 14 may include a shield portion 14 a and a baffleplate 14 b. The shield portion 14 a has a substantially cylindricalshape. The shield portion 14 a extends in a vertical direction along thesidewall of the chamber body 12 in the inner space S. The shield portion14 a is separated from the sidewall of the chamber body 12. An upper endof the shield portion 14 a extends to an upper portion of the chamber 11and is fixed to the upper portion of the chamber 11. In the plasmaprocessing apparatus 10, substrate treatment such as plasma etching isperformed in the first space S1. During the substrate treatment,by-products such as reaction products and the like are generated. Theamount of the by-products adhered to the surface of the chamber body 12is reduced by the shield portion 14 a.

The baffle plate 14 b extends in a direction orthogonal to the shieldportion 14 a. The baffle plate 14 b extends between the shield portion14 a and a supporting table to be described later. The above-describedthrough-holes of the partition wall 14 are formed in the baffle plate 14b. The shield portion 14 a and the baffle plate 14 b may be formed asone unit or may be separable from each other.

In the inner space S, a supporting part 15 extends upward from a bottomportion of the chamber body 12. The supporting part 15 has asubstantially cylindrical shape and is made of an insulating materialsuch as quartz. A supporting table 16 is mounted on the supporting part15. The supporting table 16 is supported by the supporting part 15. Thesupporting table 16 is configured to support the substrate W in thefirst space S1. The supporting table 16 includes a lower electrode 18and an electrostatic chuck 20. The supporting table 16 may furtherinclude an electrode plate 21. The electrode plate 21 is made of aconductive material such as aluminum or the like and has a substantiallydisc shape. The lower electrode 18 is provided on the electrode plate21. The lower electrode 18 is made of a conductive material such asaluminum or the like and has a substantially disc shape. The lowerelectrode 18 is electrically connected to the electrode plate 21.

A flow path 18 f is provided in the lower electrode 18. The flow path 18f is a channel for a heat exchange medium. As for the heat exchangemedium, a liquid coolant or a coolant (e.g., Freon) for cooling thelower electrode 18 by vaporization thereof is used. The heat exchangemedium is supplied to the flow path 18 f from a chiller unit through aline 22 a. The chiller unit is provided outside the chamber body 12. Theheat exchange medium supplied to the flow path 18 f is returned to thechiller unit through a line 22 b. In this manner, the heat exchangemedium is supplied to the flow path 18 f and circulates between the flowpath 18 f and the chiller unit.

The electrostatic chuck 20 is provided on the lower electrode 18. Theelectrostatic chuck 20 includes a main body and an electrode. The mainbody of the electrostatic chuck 20 is made of a dielectric material andhas a substantially disc shape. The electrode of the electrostatic chuck20 is a film-shaped electrode and is provided in the main body of theelectrostatic chuck 20. A DC power supply 23 is electrically connectedto the electrodes of the electrostatic chuck 20 through a switch 24.When a voltage is applied from the DC power supply 23 to the electrodeof the electrostatic chuck 20, an electrostatic attractive force isgenerated between the substrate W mounted on the electrostatic chuck 20and the electrostatic chuck 20. By generating the electrostaticattractive force thus generated, the substrate W is attracted to andheld on the electrostatic chuck 20.

The plasma processing apparatus 10 further includes a gas supply line25. A heat transfer gas, e.g., He gas, is supplied through the gassupply line 25 from a gas supply unit to a gap between an upper surfaceof the electrostatic chuck 20 and a backside (bottom surface) of thesubstrate W.

One or more heaters HT20 (e.g., resistance heating elements) may beprovided in the electrostatic chuck 20. Power is supplied from a heatercontroller HC20 to the heaters HT20. A high frequency filter FT20 may beprovided between the heaters HT20 and the heater controller HC20 toprevent high frequency power from flowing into the heater controllerHC20. When the heaters HT20 are provided in the electrostatic chuck 20,temperatures of a plurality of regions of the electrostatic chuck 20 canbe individually controlled by controlling the power supplied from theheater controller HC20 to the heaters HT20 individually. Accordingly, itis possible to control in-plane temperature distribution of theelectrostatic chuck 20 (i.e., in-plane temperature distribution of thesubstrate W).

A focus ring FR is disposed on an outer peripheral region of theelectrostatic chuck 20. The focus ring FR has a substantially annularplate shape. The focus ring FR is made of a silicon-containing materialsuch as silicon, quartz, or silicon carbide. The focus ring FR isdisposed to surround a peripheral edge of the substrate W. A heater HTF(e.g., resistance heating element) is provided in the focus ring FR. Theheater HTF generates heat by power supplied from a heater controllerHCF. A high frequency filter FTF may be provided between the heater HTFand the heater controller HCF to prevent high frequency power fromflowing into the heater controller HCF.

A tubular member 26 extends upward from the bottom portion of thechamber body 12. The tubular member 26 extends along an outer peripheryof the supporting part 15. The tubular member 26 is made of a conductorand has a substantially cylindrical shape. The tubular member 26 isconnected to the ground potential. A corrosion resistant film may beformed on a surface of the tubular member 26. The corrosion resistantfilm may be a film formed by anodic oxidation treatment, or a ceramicfilm made of yttrium oxide.

An insulating member 28 is provided on the tubular member 26. Theinsulating member 28 has an insulating property and is made of ceramicsuch as quartz. The insulating member 28 has a substantially cylindricalshape and extends along the outer peripheries of the electrode plate 21,the lower electrode 18, and the electrostatic chuck 20. The edge portionof the baffle plate 14 b may be provided between the tubular member 26and the insulating member 28 and may be clamped by the tubular member 26and the insulating member 28.

The supporting part 15, the supporting table 16, the tubular member 26,and the insulating member 28 constitute a support assembly SA. Thesupport assembly SA extends from the first space S1 into the secondspace S2.

The plasma processing apparatus 10 further includes an upper electrode30. The upper electrode 30 is provided above the supporting table 16.The upper electrode 30 blocks an upper opening of the chamber body 12 incooperation with a member 32. The member 32 has an insulating property.A heater HT32 (e.g., resistance heating element) may be provided in themember 32. The heater HT32 generates heat by power supplied from aheater controller HC32. The upper electrode 30 is held on an upperportion of the chamber body 12 by the member 32.

The upper electrode 30 includes a ceiling plate 34 and a holder 36. Abottom surface of the ceiling plate 34 defines the inner space S (or thefirst space S1). The ceiling plate 34 is provided with a plurality ofgas injection holes 34 a. The gas injection holes 34 a penetrate throughthe ceiling plate 34 in a plate thickness direction (verticaldirection). The ceiling plate 34 is made of, e.g., silicon, but is notlimited thereto. Alternatively, the ceiling plate 34 may have astructure in which a corrosion resistant film is formed on a surface ofa base. The corrosion resistant film may be a film formed by anodicoxidation treatment or a ceramic film made of yttrium oxide. The base ismade of a conductive material, e.g., aluminum.

The holder 36 detachably holds the ceiling plate 34. The holder 36 maybe made of a conductive material, e.g., aluminum. A heater HT36 (e.g.,resistance heating element) is provided in, e.g., the holder 36 of theupper electrode 30. The heater HT36 generates heat by power suppliedfrom a heater controller HC36. A high frequency filter FT36 may beprovided between the heater HT36 and the heater controller HC36 toprevent high frequency power from flowing into the heater controllerHC36.

A gas diffusion space 36 a is formed inside the holder 36. A pluralityof gas holes 36 b extends downward from the gas diffusion space 36 a.The gas holes 36 b communicate with the respective gas injection holes34 a. A gas inlet port 36 c is formed at the holder 36. The gas inletport 36 c is connected to the gas diffusion space 36 a. A gas supplyline 38 is connected to the gas inlet port 36 c.

A gas supply unit 40 is connected to the gas supply line 38. The gassupply unit 40 and a gas supply unit 42 to be described later constitutea gas supply system. The gas supply system is connected to the firstspace S1. The gas supply unit 40 includes a gas source (GS) group 40 s,a valve (V) group 40 a, a flow rate controller (FRC) group 40 b, and avalve (V) group 40 c.

The gas source group 40 s includes a plurality of gas sources. The gassources include a plurality of gas sources used in the method MT. Thegas sources include a gas source of one of a first gas and a second gasfor forming an organic film to be described later. Further, the gassources include one or more gas sources used for etching the organicregion OR of the substrate W. The gas sources may include an inert gassource used for a purge process to be described later.

Each of the valve group 40 a and the valve group 40 c includes aplurality of valves. The flow rate controller group 40 b includes aplurality of flow rate controllers. Each of the flow rate controllers ofthe flow rate controller group 40 b is a mass flow controller or apressure control type flow controller. The gas sources of the gas sourcegroup 40 s are respectively connected to the gas supply line 38 throughcorresponding valves of the valve group 40 a, corresponding flowcontrollers of the flow rate control group 40 b, and correspondingvalves of the valve group 40 c. The gas from the gas supply unit 40 issupplied into the first space S1 through the gas supply line 38, the gasdiffusion space 36 a, the gas holes 36 b, and the gas injection holes 34a.

The plasma processing apparatus 10 further includes a gas supply unit42. The gas supply unit 42 includes a gas source (GS) 42 s, a valve (V)42 a, a flow rate controller (FRC) 42 b, and a valve (V) 42 c. The gassource 42 s is the gas source of the other one of the first gas and thesecond gas. The flow rate controller 42 b is a mass flow controller or apressure control type flow controller. The gas source 42 s is connectedto the first space S1 through the valve 42 a, the flow rate controller42 b, and the valve 42 c. The gas from the gas supply unit 42 issupplied into the first space S1.

A gas exhaust line 50 is connected to the bottom portion of the chamberbody 12 of the plasma processing apparatus 10. A gas exhaust (GE) unit52 is connected to the gas exhaust line 50. The gas exhaust unit 52 isconnected to the second space S2 through the gas exhaust line 50. Thegas exhaust unit 52 is also connected to the first space S1 through thesecond space S2 and the through-holes of the partition wall 14. The gasexhaust unit 52 includes a pressure control valve and a depressurizationpump. The depressurization pump is connected to the second space S2through a pressure control valve. The depressurization pump may be aturbo molecular pump and/or a dry pump.

In the first space S1, the plasma processing apparatus 10 can generateplasma of the gas supplied into the first space S1. The plasmaprocessing apparatus 10 further includes a first high frequency powersupply 61. The first high frequency power supply 61 generates a firsthigh frequency power for plasma generation. The first high frequencypower has a frequency in a range from 27 MHz to 100 MHz, for example.The first high frequency power supply 61 is connected to the upperelectrode 30 through a matching unit (MU) 63. The matching unit 63 has amatching circuit for matching an output impedance of the first highfrequency power supply 61 and an impedance of a load side (the upperelectrode 30 side). Further, the first high frequency power supply 61may be connected to the lower electrode 18 via the matching unit 63. Inthat case, the upper electrode 30 is electrically grounded.

The plasma processing apparatus 10 may further include a second highfrequency power supply 62. The second high frequency power supply 62generates a second high frequency power for bias for attracting ions tothe substrate W. A frequency of the second high frequency is lower thanthe frequency of the first high frequency. The frequency of the secondhigh frequency is in a range from 400 kHz to 13.56 MHz, for example. Thesecond high frequency power supply 62 is connected to the lowerelectrode 18 through a matching unit (MU) 64. The matching unit 64 has amatching circuit for matching an output impedance of the second highfrequency power supply 62 and an impedance of a load side (the lowerelectrode 18 side).

In the plasma processing apparatus 10, when the first high frequencypower is supplied in a state in which a gas is supplied into the firstspace S1, the gas is excited. As a result, plasma is generated in thefirst space S1. When the second high frequency power is supplied to thelower electrode 18, ions in the plasma are accelerated toward thesubstrate W.

The plasma processing apparatus 10 further includes a DC power supply(DC) 70. The DC power supply 70 is connected to the upper electrode 30.The DC power supply 70 is configured to apply a negative DC voltage tothe upper electrode 30. When the negative DC voltage is applied to theupper electrode 30, positive ions in the plasma generated in the firstspace S1 collide with the ceiling plate 34 of the upper electrode 30.When the positive ions collide with the ceiling plate 34, secondaryelectrons are released from the ceiling plate 34. In the case where theceiling plate 34 is made of silicon, silicon can be released from theceiling plate 34 when the positive ions collide with the ceiling plate34.

In one embodiment, the plasma processing apparatus 10 may furtherinclude a controller 80. The controller 80 is configured to control therespective components of the plasma processing apparatus 10. Thecontroller 80 may be a computer including a processor, a storage devicesuch as and a memory, an input device, a display device, and the like.The controller 80 executes a control program stored in the storagedevice and controls the respective components of the plasma processingapparatus 10 based on a recipe data stored in the storage device.Accordingly, the plasma processing apparatus 10 executes a processspecified by the recipe data. For example, the controller 80 controlsthe respective components of the plasma processing apparatus 10 inexecuting the method MT.

Referring back to FIG. 1, the method MT will be described in detail. Inthe following description, the case in which the method MT is performedby using the plasma processing apparatus 10 will be described as anexample. Further, the following description will be described withreference to FIGS. 4 to 8. FIGS. 4, 6, 7, and 8 schematically show innerstates of the chamber of the exemplary plasma processing apparatusduring the execution of the method shown in FIG. 1. FIG. 5 is apartially enlarged cross-sectional view of the exemplary substrate afterexecution of step ST2 of the method shown in FIG. 1.

First, step ST1 of the method MT is executed. During the execution ofstep ST1, the substrate W is not mounted on the supporting table 16 andis not disposed in the chamber 11. During the execution of step ST1, theshutter SH may open or close the opening of the partition wall 14. Instep ST1, as shown in FIG. 4, an organic film OF is formed. The organicfilm OF is formed on a surface extending out around a region WR. Theregion WR is a region in the chamber 11 where the substrate W ismounted. In one example, the region WR is disposed directly above thesupporting table 16 (electrostatic chuck 20). In other words, theorganic film OF is formed at least on a surface radially extendingaround the substrate W with respect to the center of the substrate W.

In the case of using the plasma processing apparatus 10, the organicfilm OF is formed on a surface that defines the first space S1.Specifically, the organic film OF is formed on a surface 14 e of thepartition wall 14, a surface 30 e of the upper electrode 30, and asurface 32 e of the member 32. The surface 14 e defines the first spaceS1 in the entire surface of the partition wall 14. The surface 30 edefines the first space S1 in the entire surface of the upper electrode30, e.g., a bottom surface of the ceiling plate 34. The surface 32 edefines the first space S1 in the entire surface of the member 32. Theorganic film OF may or may not be formed on a surface that defines thefirst space S1 in the entire surface of the focus ring FR. The organicfilm OF may or may not be formed on a surface that defines the firstspace S1 in the entire surface of the insulating member 28.

In step ST1 of one embodiment, the first gas and the second gas arealternately or simultaneously supplied to the first space S1 in order toform the organic film OF. The first gas and the second gas are alsosupplied to the second space S2 through the first space S1. One of thefirst gas and the second gas is supplied by the gas supply unit 40. Theother one of the first gas and the second gas is supplied by the gassupply unit 42. In step ST1, the gas exhaust unit 52 is controlled toset a pressure in the inner space S to a specified pressure. In stepST1, plasma is not generated in the inner space S.

In the case where the first gas and the second gas are alternatelysupplied to the first space S1 in step ST1, the inner space S may bepurged after the supply of the first gas and before the supply of thesecond gas. In the case where the first gas and the second gas arealternately supplied to the first space S1 in step ST1, the inner spaceS may be purged after the supply of the second gas and before the supplyof the first gas. The inner space S is purged by exhausting the gas inthe inner space S by the gas exhaust unit 52. When the inner space S ispurged, an inert gas may be supplied from the gas supply unit 40 to theinner space S. The inert gas is, e.g., a rare gas or a nitrogen gas.

The first gas contains a first organic compound. The second gas containsa second organic compound. The organic film OF is formed bypolymerization of the first organic compound and the second organiccompound. The polymerization of the first organic compound and thesecond organic compound occurs at a temperature within a firsttemperature range of, e.g., 0° C. to 150° C. In other words, thepolymerization of the first organic compound and the second organiccompound does not occur at a temperature within a second temperaturerange which is lower than the lower limit of the first temperaturerange. Further, the polymerization of the first organic compound and thesecond organic compound does not occur at a temperature within a thirdtemperature range of, e.g., 250° C. to 400° C., which is higher than theupper limit of the first temperature range. The organic compound formedby the polymerization of the first organic compound and the secondorganic compound may be depolymerized to the first organic compound andthe second organic compound at a temperature within the thirdtemperature range.

In step ST1 of one embodiment, one or more components having theaforementioned surfaces are heated to selectively form the organic filmOF on those surfaces. Specifically, each of the components is heated toa temperature within the first temperature range by the heater providedtherein. For example, the partition wall 14, the upper electrode 30, andthe member 32 are heated by the respective heaters HT14, HT30, and HT32to a temperature within the first temperature range. As a result, theorganic film OF is formed on the surface 14 e of the partition wall 14,the surface 32 e of the member 32, and the surface 30 e of the upperelectrode 30. The organic film OF is also formed on a surface 14 f thatdefines the second space S2 in the entire surface of the partition wall14.

When the partition wall 14 and the insulating portion 28 are fastened toeach other by means of, e.g., screws, a temperature of the insulatingmember 28 is also within the first temperature range. In this case, theorganic film OF is also formed on the surface of the insulating member28 in step ST1. When the focus ring FR is heated to a temperature withinthe first temperature range by the heater HTF, the organic film OF isalso formed on the surface of the focus ring FR in step ST1.

During the execution of step ST1, the temperature of the supportingtable 16 is set to a temperature within the second temperature range orthe third temperature range. When the temperature of the supportingtable 16 is set to the temperature within the second temperature range,the coolant is supplied to the flow path 18 f. When the temperature ofthe supporting table 16 is set to the temperature within the thirdtemperature range, the electrostatic chuck 20 is heated by the heaterHT20. The contact area between the focus ring FR and each of thesupporting table 16 (the electrostatic chuck 20) and the insulatingmember 28 is small. Therefore, the focus ring FR is thermally separatedfrom the supporting table 16 and the insulating member 28. The contactarea between the insulating member 28 and the supporting table 16 isalso small. Therefore, the insulating portion 28 is thermally separatedfrom the supporting table 16. Accordingly, the temperatures of the focusring FR, the supporting table 16, and the insulating member 28 can beindividually controlled.

Hereinafter, the description will be made on examples of the firstorganic compound, the second organic compound, and the organic compoundproduced by the polymerization of the first organic compound and thesecond organic compound, i.e., the organic compound forming the organicfilm OF.

The first organic compound may be isocyanate shown in the followingformula (1) or (2). The second organic compound may be amine shown inthe following formula (3) or (4). In other words, the first organiccompound may be monofunctional isocyanate or difunctional isocyanate,and the second organic compound may be monofunctional amine ordifunctional amine.<Formula 1>OCN—R  (1)<Formula 2>OCN—R—NCO  (2)<Formula 3>H₂N—R  (3)<Formula 4>H₂N—R—NH₂  (4)

In the formulas (1) and (2), R represents a saturated hydrocarbon groupsuch as an alkyl group (linear alkyl group or cyclic alkyl group) or thelike, an unsaturated hydrocarbon group such as an aryl group or thelike, or a group containing a heteroatom such as N, O, S, F, Si or thelike. The group containing the heteroatom includes an unsaturatedhydrocarbon group or a saturated hydrocarbon group whose elements arepartially substituted with N, O, S, F, Si, or the like. As for theisocyanate that is the first organic compound, an aliphatic compound oran aromatic compound may be used, for example. As for the aliphaticcompound, an aliphatic chain compound or an aliphatic cyclic compoundmay be used. The aliphatic compound may include, e.g., hexamethylenediisocyanate. The aliphatic cyclic compound may include, e.g., 1,3-bis(isocyanatomethyl) cyclohexane (H6XDI).

In the formulas (3) and (4), R represents a saturated hydrocarbon groupsuch as an alkyl group (linear alkyl group or a cyclic alkyl group) orthe like, an unsaturated hydrocarbon group such as an aryl group or thelike, or a group containing a heteroatom such as N, O, S, F, Si or thelike. The group containing the heteroatom includes an unsaturatedhydrocarbon group or a saturated hydrocarbon group whose elements arepartially substituted with N, O, S, F, Si, or the like. The atomic grouprepresented by R in the formula (1) or (2) may be the same as ordifferent from the atomic group represented by R in the formula (3) or(4). As for the amine that is the second organic compound, an aliphaticcompound or an aromatic compound may be used, for example. As for thealiphatic compound, an aliphatic chain compound or an aliphatic cycliccompound may be used. The aliphatic compound may include, e.g.,1,12-diaminododecane (DAD). The aliphatic cyclic compound may include1,3-bis (aminomethyl) cyclohexane (H6XDA). The amine that is the secondorganic compound may be secondary amine.

As for the organic compound obtained by polymerization of isocyanate andamine (addition condensation), compounds having a urea bond shown in thefollowing formulas (5) to (8) may be used. The compound shown in theformula (5) is produced by polymerization of the compound shown in theformula (1) and the compound shown in the formula (3). The compoundshown in the formula (6) is produced by polymerization of the compoundshown in the formula (1) and the compound shown in the formula (4).Alternatively, the compound shown in the formula (6) is produced bypolymerization of the compound shown in the formula (2) and the compoundshown in the formula (3). The compound shown in the formula (7) isproduced by polymerization of the compound shown in the formula (2) andthe compound shown in the formula (4). The compound shown in the formula(8) has a structure in which both ends of the polymer shown in theformula (7) are terminated with a monomer having an isocyanate group(e.g., the compound shown in the formula (1)) and a monomer having anamino group (e.g., the compound shown in the formula (3)). In theformulas (7) and (8), n is an integer of 2 or more.

In another example, the first organic compound may be isocyanate shownin the formula (1) or (2), and the second organic compound may be acompound having a hydroxyl group shown in the following formula (9) or(10). In other words, the first organic compound may be monofunctionalisocyanate or difunctional isocyanate, and the second organic compoundmay be a monofunctional compound having a hydroxyl group or adifunctional compound having a hydroxyl group.<Formula 9]>HO—R  (9)<Formula 10>HO—R—OH  (10)

In the formulas (9) and (10), R represents a saturated hydrocarbon groupsuch as an alkyl group (linear alkyl group or cyclic alkyl group) or thelike, an unsaturated hydrocarbon group such as an aryl group or thelike, or a group containing a heteroatom such as N, O, S, F, Si or thelike. The group containing the heteroatom includes an unsaturatedhydrocarbon group or a saturated hydrocarbon group whose elements arepartially substituted with N, O, S, F, Si, or the like. The atomic grouprepresented by R in the formulas (1) and (2) may be the same as ordifferent from the atomic group represented by R in the formulas (9) and(10). The compound having a hydroxyl group is alcohol or phenol. As forthe alcohol that is the second organic compound, ethylene glycol can beused, for example. As for the phenol that is the second organiccompound, hydroquinone can be used, for example.

As for another organic compound obtained by polymerization (polyaddition) of isocyanate and a compound having a hydroxyl group,compounds having a urethane bond shown in the following formulas (11) to(15) can be used. The compound shown in the formula (11) is produced bypolymerization of the compound shown in the formula (1) and the compoundshown in the formula (9). The compound shown in the formula (12) isproduced by polymerization of the compound shown in the formula (1) andthe compound shown in the formula (10). The compound shown in theformula (13) is produced by polymerization of the compound shown in theformula (2) and the compound shown in the formula (9). The compoundshown in the formula (14) is produced by polymerization of the compoundshown in the formula (2) and the compound shown in the formula (10). Thecompound shown in the formula (15) has a structure in which both ends ofthe polymer shown in the formula (14) are terminated with a monomerhaving an isocyanate group (e.g., the compound shown in the formula (1))and a monomer having a hydroxyl group (e.g., the compound shown in theformula (9)). In the formulas (14) and (15), n is an integer of 2 ormore.

In still another example, the first organic compound may be carboxylicacid shown in the following formula (16) or (17), and the second organiccompound may be amine shown in the formula (3) or (4). In other words,the first organic compound can be monofunctional carboxylic acid ordifunctional carboxylic acid, and the second organic compound can bemonofunctional amine or difunctional amine.<Formula 16>HOOC—R  (16)<Formula 17>]HOOC—R—COOH  (17)

In the formulas (16) and (17), R represents a saturated hydrocarbongroup such as an alkyl group (a linear alkyl group or a cyclic alkylgroup) or the like, an unsaturated hydrocarbon group such as an arylgroup or the like, or a group containing a heteroatom such as N, O, S,F, or Si or the like. The group containing the heteroatom includes anunsaturated hydrocarbon group or a saturated hydrocarbon group whoseelements are partially substituted with N, O, S, F, Si, or the like. Theatomic group represented by R in the formulas (3) and (4) may be thesame as or different from the atomic group represented by R in theformulas (16) and (17). The carboxylic acid that is the first organiccompound may be, e.g., terephthalic acid.

As for the organic compound obtained by polymerization (polycondensation) of carboxyl acid and amine, compounds having an amide bondshown in the following formulas (18) to (22), e.g., polyamide can beused. The compound shown in the formula (18) is produced bypolymerization of the compound shown in the formula (16) and thecompound shown in the formula (3). The compound shown in the formula(19) is produced by polymerization of the compound shown in the formula(16) and the compound shown in the formula (4). The compound shown inthe formula (20) is produced by polymerization of the compound shown inthe formula (17) and the compound shown in the formula (3). The compoundshown in the formula (21) is produced by polymerization of the compoundshown in the formula (17) and the compound shown in the formula (4). Thecompound shown in the formula (22) has a structure in which both ends ofthe polymer shown in the formula (21) are terminated with a monomerhaving a carboxyl group (e.g., the compound shown in the formula (16))and a monomer having an amino group (e.g., the compound shown in theformula (3)). In the formulas (21) and (22), n is an integer of 2 ormore. The polymerization reaction of carboxylic acid and amine produceswater molecules. The produced water molecules are exhausted from theprocessing space under a depressurized environment. Therefore, thepolymerization reaction of carboxylic acid and amine is irreversible.

The first organic compound used for polymerization with the amine shownin the formula (3) or (4) may be carboxylic acid halide shown in thefollowing formula (23). In the formula (23), X is F, Cl, Br, or I. Theatomic group represented by R in the formula (23) may be the same as ordifferent from the atomic group represented by R in the formulas (16)and (17).

In still another example, the first organic compound may be carboxylicacid shown in the formula (16) or (17), and the second organic compoundmay be a compound having a hydroxyl group shown in the formula (9) or(10). In other words, the first organic compound may be monofunctionalcarboxylic acid or difunctional carboxylic acid, and the second organiccompound may be a monofunctional compound having a hydroxyl group or adifunctional compound having a hydroxyl group. The atomic grouprepresented by R in formulas (16) and (17) may be the same as ordifferent from the atomic group represented by R in formulas (9) and(10).

As for the organic compound obtained by polymerization (polycondensation) of carboxylic acid and a compound having a hydroxyl group,a compound having an ester bond shown in the following formulas (24) to(28), e.g., polyester, can be used. The compound shown in the formula(24) is produced by polymerization of the compound shown in the formula(16) and the compound shown in the formula (9). The compound shown inthe formula (25) is produced by polymerization of the compound shown inthe formula (16) and the compound shown in the formula (10). Thecompound shown in the formula (26) is produced by polymerization of thecompound shown in the formula (17) and the compound shown in the formula(9). The compound shown in the formula (27) is produced bypolymerization of the compound shown in the formula (17) and thecompound shown in the formula (10). The compound shown in the formula(28) has a structure in which both ends of the polymer shown in theformula (27) are terminated with a monomer having a carboxyl group(e.g., the compound shown in the formula (16)) and a monomer having ahydroxyl group (e.g., the compound shown in the formula (9)). In theformulas (27) and (28), n is an integer of 2 or more. The polymerizationreaction of the carboxylic acid and the compound having the hydroxylgroup produces water molecules. The produced water molecules areexhausted from the processing space under a depressurized environment.Therefore, the polymerization reaction of the carboxylic acid and thecompound having the hydroxyl group is irreversible.

The first organic compound used for polymerization with the compoundhaving the hydroxyl group shown in the formula (9) or (10) may becarboxylic acid halide shown in the formula (23).

In still another example, the first organic compound may be carboxylicacid anhydride shown in the following formula (29) or (30), and thesecond organic compound may be amine shown in the formula (3) or (4).

In the formulas (29) and (30), R represents a saturated hydrocarbongroup such as an alkyl group (linear alkyl group or cyclic alkyl group)or the like, an unsaturated hydrocarbon group such as an aryl group orthe like, or a group containing a heteroatom such as N, O, S, F, Si orthe like. The group containing the heteroatom includes an unsaturatedhydrocarbon group or a saturated hydrocarbon group whose elements arepartially substituted with N, O, S, F, Si, or the like. The atomic grouprepresented by R in formulas (29) and (30) may be the same as ordifferent from the atomic group represented by R in formulas (3) and(4). The carboxylic acid anhydride that is the first organic compoundmay be, e.g., pyromellitic dianhydride.

The organic compound obtained by polymerization of carboxylic acidanhydride and amine may be, e.g., an imide compound shown in thefollowing formula (31) or formula (32). The compound shown in theformula (31) is produced by polymerization of the compound shown in theformula (29) and the compound shown in the formula (3). The compoundshown in the formula (32) is produced by polymerization of the compoundshown in the formula (30) and the compound shown in the formula (4). Inthe formulas (31) and (32), n is an integer of 2 or more. Thepolymerization reaction of carboxylic anhydride and amine produces watermolecules. The produced water molecules are exhausted from theprocessing space under a depressurized environment. Therefore, thepolymerization reaction of carboxylic acid anhydride and amine isirreversible. In the polymerization of carboxylic anhydride and amine,monofunctional carboxylic anhydride, difunctional carboxylic anhydride,monofunctional amine, and difunctional amine may be used.

In the method MT, subsequent to step ST1, the substrate W is loaded intothe chamber 11 and mounted on the supporting table 16. The substrate Wis held by the electrostatic chuck 20.

Next, in the method MT, step ST2 is executed. During the execution ofstep ST2, the shutter SH closes the opening of the partition wall 14. Instep ST2, the organic region OR of the substrate W is etched. Theorganic region OR is etched by chemical species from the plasma in thechamber 11 (in the first space S1).

In step ST2, the processing gas is supplied to the inner space S (thefirst space S1). The processing gas may contain any gas as long as theorganic region OR can be etched. The processing gas may contain anoxygen-containing gas. The oxygen-containing gas may be an oxygen gas(O₂ gas), a CO gas, or a CO₂ gas. Alternatively, the processing gas maybe a gaseous mixture of a hydrogen gas (H₂ gas) and a nitrogen gas (N₂gas). In step ST2, the gas exhaust unit 52 is controlled to set apressure in the inner space S to a specified pressure. Further, in stepST2, the first high frequency power is supplied to generate plasma ofthe processing gas. The second high frequency power may be supplied ormay not be supplied.

In step ST2, the plasma of the processing gas is generated in the innerspace S (the first space S1). In step ST2, the organic region OR isetched by chemical species from the plasma of the processing gas asshown in FIG. 5. The chemical species from the plasma may mainly containradicals. The chemical species from the plasma may contain ions as wellas radicals. The chemical species from the plasma are consumed not onlyby the etching of the organic film OF as well as the plasma etching ofthe organic region OR of the substrate W. The organic film OF is formedon the surface extending out around the region WR where the substrate Wis disposed. Therefore, the variation in the amount of consumption ofthe chemical species depending on positions in the chamber 11 issuppressed. As a result, the variation in the density of the chemicalspecies depending on positions on the substrate W is also suppressed.Accordingly, according to the method MT, high in-plane uniformity isobtained in the plasma etching of the organic region OR.

In one embodiment, a sequence including steps ST1 and ST2 may berepeated. The sequence may be repeated to etch the organic regions OR ofa plurality of substrates. After the execution of step ST2, the organicfilm OF may remain on the aforementioned surfaces as shown in FIG. 6. Inone embodiment, the organic film OF on the surfaces that define thefirst space S1 are removed before the next sequence is executed.Therefore, the method MT may include step ST3 as shown in FIG. 1. Inother words, the sequence may include step ST3 in addition to steps ST1and ST2.

In step ST3 of one embodiment, the organic film OF is removed by plasmacleaning. Specifically, a cleaning gas is supplied to the inner space S(the first space S1). The cleaning gas may contain any gas as long as itcan remove the organic film OF. The cleaning gas may containoxygen-containing gas. The oxygen-containing gas may be an oxygen gas(O₂ gas), a CO gas, or a CO₂ gas. Alternatively, the cleaning gas may bea gaseous mixture of a hydrogen gas (H₂ gas) and a nitrogen gas (N₂gas). In step ST3, the gas exhaust unit 52 is controlled to set apressure in the inner space S to a specified pressure. Further, in stepST3, the first high frequency power is supplied to generate plasma ofthe cleaning gas. The second high frequency power may be supplied or maynot be supplied. During the execution of step ST3, the shutter SH closesthe opening of the partition wall 14. In step ST3 of the presentembodiment, the organic film OF is removed from the surfaces that definethe first space S1 by active species from the plasma of the cleaninggas, as shown in FIG. 7. Since the active species from the plasma hardlyreach the second space S2, the organic film OF remains on the surfacethat defines the second space S2. Further, during the execution of stepST3 of the present embodiment, a dummy substrate DW may be mounted onthe supporting table 16 (electrostatic chuck 20). Alternatively, duringthe execution of step ST3 of the present embodiment, an object may notbe mounted on the supporting table 16 (electrostatic chuck 20).

In another embodiment, step ST3 may be applied to the case in which theorganic film OF is made of an organic compound produced bypolymerization of isocyanate and amine or an organic compound producedby polymerization of isocyanate and a compound having a hydroxyl group.In step ST3 of this embodiment, one or more components on which theorganic film OF is formed are heated to a temperature within the thirdtemperature range. During the execution of step ST3, the shutter SHcloses the opening of the partition wall 14. In step ST3 of thisembodiment, the partition wall 14, the upper electrode 30, and themember 32 are heated to a temperature within the third temperature rangeby the heaters HT14, HT30, and HT32, respectively. When the organic filmOF is also formed on the focus ring FR, the focus ring FR is heated to atemperature within the third temperature range by the heater HTF. As aresult, depolymerization of the organic compound forming the organicfilm OF occurs. The gas of the organic compound due to depolymerizationis exhausted. Accordingly, the organic film OF is removed from thesurfaces that define the inner space S as shown in FIG. 8.

Next, in step ST4, it is determined whether or not a terminationcondition for the method MT is satisfied. The termination condition isdetermined to be satisfied when the number of executions of the sequenceincluding steps ST1 and ST2 has reached a predetermined number. If it isdetermined in step ST4 that the termination condition is not satisfied,the sequence including steps ST1 and ST2 is executed again. On the otherhand, if it is determined in step ST4 that the termination conditionsare satisfied, the execution of the method MT is terminated.

While various embodiments have been described, various modifications canbe made without being limited to the above-described embodiments. Forexample, the method MT may be performed by using a plasma processingapparatus other than the plasma processing apparatus 10. Such a plasmaprocessing apparatus may be an inductively coupled plasma processingapparatus, or a plasma processing apparatus for generating plasma by asurface wave such as a microwave.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made departing from the spirit of the disclosures. Theaccompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

The invention claimed is:
 1. A method for etching an organic region of asubstrate, comprising: forming an organic film on a surface in a chamberof a plasma processing apparatus, the surface extending out around aregion where the substrate is to be disposed in the chamber of theplasma processing apparatus; and etching the organic region withchemical species from plasma in the chamber, wherein in said forming theorganic film, a first gas containing a first organic compound and asecond gas containing a second organic compound are supplied into thechamber, and the organic film is formed by polymerization of the firstorganic compound and the second organic compound.
 2. The method of claim1, wherein a heater is provided in each of one or more components thatdefine the surface in the plasma processing apparatus, and in saidforming the organic film, the components are heated such that thepolymerization occurs selectively on the surface.
 3. The method of claim2, wherein a sequence including said forming the organic film and saidetching the organic region repeated, and the method further comprises,between said etching the organic region and said forming the organicfilm, removing the organic film by plasma cleaning.
 4. The method ofclaim 2, wherein a sequence including said forming the organic film andsaid etching the organic region is repeated, and the method furthercomprises, between said etching the organic region and said forming theorganic film, removing the organic film by depolymerization of theorganic film.
 5. The method of claim 4, wherein the first organiccompound is isocyanate and the second organic compound is amine or acompound having a hydroxyl group.
 6. The method of claim 1, wherein asequence including said forming the organic film and said etching theorganic region is repeated, and the method further comprises, betweensaid etching the organic region and said forming the organic film,removing the organic film by plasma cleaning.
 7. The method of claim 1,wherein a sequence including said forming the organic film and saidetching the organic region is repeated, and the method furthercomprises, between said etching the organic region and said forming theorganic film, removing the organic film by depolymerization of theorganic film.
 8. The method of claim 7, wherein the first organiccompound is isocyanate and the second organic compound is amine or acompound having a hydroxyl group.
 9. The method of claim 1, wherein thechamber has an inner space which includes a first space and a secondspace, with the first space and the second space being divided by apartition wall, and in said forming the organic film, the organic filmis formed on a surface which defines the first space.
 10. The method ofclaim 1, wherein the chamber includes a chamber body, with the chamberbody having an inner space which includes a first space and a secondspace and with the first space and the second space being divided by apartition wall, the plasma processing apparatus includes an upperelectrode and a member, with the upper electrode blocking an upperopening of the chamber body in cooperation with the member, and in saidforming the organic film, the organic film is formed on a surface of thepartition wall, a surface of the upper electrode and a surface of themember.
 11. The method of claim 10, wherein the partition wall includesan opening through which the substrate is transferred between the firstspace and an outside of the chamber and a shutter which opens and closesthe opening of the partition wall, and the forming of organic film isperformed while the shutter opens the opening of the partition wall. 12.The method of claim 1, wherein, in said forming the organic film, thesurface extending out around the region where the substrate is to bedisposed is heated to a temperature within a first temperature range andthe region where the substrate is to be disposed is set to a temperaturewithin a second temperature range or a third temperature range, andwherein the second temperature range is lower than a lower limit of thefirst temperature range and the third temperature range is higher thanan upper limit of the first temperature range.
 13. The method of claim12, wherein the first temperature range is from 0° C. to 150° C. and thethird temperature range is from 250° C. to 400° C.
 14. The method ofclaim 1, wherein the first organic compound is isocyanate or carboxylicacid and the second organic compound is amine or a compound having ahydroxyl group.
 15. The method of claim 1, wherein said forming theorganic film is performed while the substrate is not disposed in thechamber, and the method further comprises, between said forming theorganic film and said etching the organic region, loading the substrateinto the chamber.
 16. The method of claim 1, wherein the first gas andthe second gas are supplied into the chamber simultaneously.
 17. Themethod of claim 1, wherein the first gas and the second gas aresuppliedinto the chamber alternately.
 18. The method of claim 17,wherein the chamber is purged after the supply of the first gas andbefore the supply of the second gas or after the supply of the secondgas and before the supply of the first gas.
 19. The method of claim 1,wherein, in said etching the organic region, the plasma is generatedfrom an oxygen-containing gas or a gaseous mixture of a hydrogen gas anda nitrogen gas.